This invention relates generally to scraping tools of the type that employ replaceable sharp-edged blades such as razors, utility and wallpaper blades and more particularly those utilizing a storage area and are ergonomically designed.
1. Background
A wide variety of prior art tool heads and blade clamps exist in the field of this invention. Some examples of prior art include, generally, clamps having two jaws, or lips, that are attached to each other by one or more screws, thus necessitating a screwdriver or some other suitable implement to assemble or replace a blade. Such clamps may retain the blade solely by the friction resulting from the clamping force, or, as in some models, by one or more interlocking detents in one of the clamping surfaces that engage a mating hole or holes in the blade. These types of clamps are usually found on wallpaper shaving tools.
The design of these types of tools makes the removal and replacement of blades inconvenient. In order to replace a worn blade, a user must have another tool such as a screwdriver or Allen wrench to loosen the attachment screw(s). Once the screw(s) are loosened, the blade is released and there is an increased probability that the blade will fall from the clamp onto the floor or ground. The user must then pick it up for safe disposal. The screw(s) can also be inadvertently loosened so much that they fall out of the clamp onto the floor or ground, increasing the probability of their becoming lost. This results in wasted time finding the lost or a new screw or, if not found, the user might unsafely or inefficiently operate the scraper with less screws than designed. Also most scrapers are made of metal with the sliding or loading of a metal blade into a metal holder can be difficult. The metal on metal does not often slide easily thus requiring a user to push the blade against a solid object like a table or wall putting tension and wear on the blade and creating a very unsafe situation for the user, this can even cause the blade to break. There are some devices that have a side loading of the blades but they require mulitple steps and locking procedures. There is a need of an easy one touch loading of a blade.
Further, some users tend to hold the tool up in the air with one hand while tightening or loosening the screws with the other. It's possible even to cradle the clamp in either hand so as to employ the thumb and forefinger as guides for the edges of the blade, maintaining its position and alignment while the clamp is loose. Users could more easily lose their grip on the screwdriver of the scraping tool when handling it in this manner, resulting in bodily injury.
There are many other types of prior art clamps for utility, razor, window scraper and other styles of blades employed in scraping tools, all having deficiencies of one type or another, as noted in the ensuing descriptions. Many do not have a place where you can store extra blades for easy accessibility. There needs to be an area that is reaccessible.
Most prior art scraping tools are made of metal which can be slippery when wet oand unconferable to hold of long periods. The metal also presents problems when there are changes in the weather such as cool and heat. When it is cool the metal is cold to the hand and can become brittle. When it is hot, the metal can burn the hand.
The absence of a storage place for extra blades on most scrapers, and the location/lack of inaccessability of the storage areas on those that do have them presents a problem. If a blade breaks or gets dull in the middle of a project it can take time to go and get a blade and replace. Spare blades have to be stored carefully as they can be a safety hazard and they also need to be easily accessible. For those few scrapers the have storage areas, many of those you need to have an extra tool like a screw driver to open the scraper up to get to the extra blades. Other storage areas are designed to handle either packed or single blades, both not both. Some have a swivel opening, turning a single connecting point in the handle making it more difficult to hold the scraper while changing the blade. Many of these require you to remove the blades from their packaging.
These prior scraping tools were not ergonomically designed so that using them can cause strain on the user and may even cause repetitive motion damages. The lack of an ergonomic design makes it harder for a person to use the scraping tool.
2. Description of Prior Art
There have been various types of scrapers designed over the years. In using a scraper that utilizes a razor blade, it is important that the bare blade be covered when the scraper is not in use in order to prevent the bare blade from injuring someone and to protect the blade edge. Therefore, some prior scrapers place a blade in a retractable holder so that when the blade is not in use, the holder with the blade is retracted within a casing so as to hide the blade. Other scrapers have used protective covers which are pivotally moved to a position to hide the exposed blade edge. Still other scrapers have covers which are moved over the blade and are locked in place by tightening a set screw or some other device. Examples of these scrapers are shown and described in U.S. Pat. Nos. 2,336,284, 2,580,182 and 3,667,122.
U.S. Pat. No. 4,575,936 issued Mar. 18, 1986, titled “Blade Retaining Tool Head” attempts to remedy the hazard and inconvenience of the prior art screw-type clamp. This is done by employing interlocking, pivoting clamp-halves that are actuated by a threaded handle which engages mating threads in each clamp-half. A filled-in thread in one of the clamp-halves augments a camming action that forces the two halves together to grip an inserted blade when the handle is fully tightened. This eliminates the need for screws and a screwdriver or other tools to perform this function.
The U.S. Pat. No. 4,575,936 patent, however, provides no means for retaining the blade while the clamp is being actuated, perpetuating the potential hazard caused by a user's tendency to guide the edges of the blade into alignment with the clamp with one hand while tightening or loosening the threaded handle with the other.
Additionally, the amount of clamping force imposed on the blade, and thus the magnitude of the retaining friction force, depends on the degree of tightening-torque applied to the handle by the user and, of course, the amount of wear on the resilient cylinder. Whether by inexperience, insufficient strength or lack of intuitive insight, the user may fail to apply enough torque to the handle to sufficiently clamp the blade for all aspects of its intended use. Also, when loosening the clamp to change blades, the user may, for the same reasons, inadvertently disassemble the handle from the clamp-halves; an inconvenience, at the least.
U.S. Pat. No. 5,056,226 issued Oct. 15, 1991, titled “Tool For Carrying a Scraping or Stripping Blade” specifies a two-piece device incorporating a pivot able, lever-actuated blade clamp. The U.S. Pat. No. 5,056,226 patent requires no auxiliary tool, such as a screwdriver, to install or remove a blade.
But as in the U.S. Pat. No. 4,575,936 patent, the U.S. Pat. No. 5,056,226 patent provides no means for containing or restraining the blade during the period between the time it is placed in the clamp and the time that the lever is latched shut. Hence, the potential inconvenience of a loose blade slipping, or falling from the clamp before it's closed tightly on the blade persists. The tool bearing the U.S. Pat. No. 5,056,226 number includes two detents in the lower, fixed clamp jaw that engage corresponding holes in the blade, offering a limited amount of blade restraint at times when the lever is unlatched. However, this effect is far from positive blade retention. Another class of clamps for scraping applications are those that incorporate retractable slides upon or within which the blade is placed or inserted.
U.S. Pat. No. 4,955,138 issued Sep. 11, 1990 titled “Utility Blade Scraper” incorporates a thumb button actuated trigger and slide, lockable in three positions: (1) fully retracted; (2) working position (partial extension) and (3) blade changing position (full extension).
The blade is loaded in the latter position by placing it on the extended slides; a central hole in the blade engaging the slide's mating detent. Additionally, two “lugs” on the slide engage slots in the back edge of the blade. Upon first placing the blade on the slide it will tend to stay in place as long as the handle is held horizontally, but otherwise may become dislodged and fall, resulting in lost or damaged blades and wasted time and inconvenience. Also, the blade may require some guidance by the user as it is retracted through the blade slot opening. The back edge of the blade may tend to hang-up on the upper edge of the slot, or, in some instances, so may the blade positioning detent. Once retracted into the confines of the slot, the blade is contained by the upper and lower internal surfaces of the slot.
Finally, there's the common razor blade scraper with a myriad of forms and styles. The types most relevant to the field of this invention are the retractable varieties as exemplified by Harry Warner et al U.S. Pat. No. 2,291,514 issued Jul. 28, 1942, Donald Gringer U.S. Pat. No. 4,558,517 issued Dec. 17, 1985 and Leon Lavallee, et al Pat. No. D346,319 issued Apr. 26, 1994.
There are numerous scraping tools on the market, many of which are the subject matter of patents. Such patents include: U.S. Pat. Nos. 6,334,254, 6,286,215, 6,253,454, 6,101,721, 5,996,231, 5,924,203, 5,713,232, 5,528,832, 5,493,781, 5,433,004, 5,319,853, 5,235,751, 5,181,320, 5,095,573, 5,009,099, 4,979,300, 4,558,517, 4,238,883, 4,182,033, D396,910, D389,966, D386,846, D383,577, D358,011, D346,319, D338,822, D362,093, D282,881 and D274,953. Yet these patents do not solve the need for a scraping tool that allows the blade to be replaced easily while having a storage compartment for blades while being ergonomically designed.
For the foregoing reasons, there is a need for a scraping tool with easy one touch loading and replacing the blade, easy to access storage compartment, made of a two components plastic and ergonomic design.